Plastic bag for vacuum sealing

ABSTRACT

A plastic bag for vacuum sealing that has a folding line formed during fabrication of a plastic bag to form an air channel communicating with a housing chamber so that when the plastic bag is coupled on a vacuum sealing machine remaining air in the housing chamber may be fully extracted before the plastic bag is sealed.

FIELD OF THE INVENTION

The present invention relates to a plastic bag for vacuum sealing andparticularly to a plastic bag for holding goods that has a suctionpocket for extracting remaining air then be sealed to prevent externalair from entering to protect the quality of the goods.

BACKGROUND OF THE INVENTION

In the general household preserving goods that easily rust or perish isa commonly encountered problem, especially for food. While freshvegetables and fruits may be held in containers and stored in arefrigerator to maintain the freshness, the general foodstuffs such asbiscuits, potato chips, candies cannot be stored in the refrigeratoronce unpacked and not consumed immediately. They tend to lose theoriginal tasty flavor after having exposed to the air. To remedy thisproblem, many vendors have developed household sealing machines so thatusers can store goods to be preserved in an air impermeablethermoplastic bag and extract the remaining air from the thermoplasticbag, and seal the opening of the plastic bag. Thereby the goods canmaintain their original taste next time they are removed from theplastic bag.

Owing to the housing chamber of the plastic bag has a selected length,when the sealing machine starts suction and extracts the air, the airaround the bag opening is extracted immediately. As the plastic bag ismade from thermoplastic material which has viscosity, extracting the airaround the bag opening tends to make the sealing machine mistakenlyjudge that the remaining air in the housing chamber has been completelyextracted and proceed sealing operation. As a result, there is still airtrapped inside the housing chamber coexisting with the goods heldinside. The sealing effect is compromised. In order to remedy thisproblem, U.S. Pat. No. 4,756,422 (RE34,929) discloses a plastic bag forvacuum sealing. It has air channels formed in a spaced pattern by heatembossing on at least one air impermeable layer to communicate thehousing chamber with the bag opening. Through the air channels, theplastic bag opening does not partially seal and all the air in theplastic bag may be extracted before the sealing machine starts sealingoperation.

Nevertheless, the cited reference mentioned above has to form the airchannels by heat embossing, and the air impermeable layer of the plasticbag has to be thickened. Hence, not only the fabrication process is morecomplicated the costs of fabrication and material increase greatly andthe products become more expensive as well. With increased thickness,more sealing time is required. As most sealing machines are designed tostop air extraction during the sealing process, while the plastic bag issealed, the air tends to reenter the plastic bag through the airchannels, and the actual air extracting and sealing effect is notdesirable.

Other references also can be found in U.S. Pat. Nos. 3,809,217 and4,093,068.

SUMMARY OF THE INVENTION

The primary object of the present invention is to solve the aforesaiddisadvantages. The invention provides a plastic bag that has an airchannel communicating the bag opening with the housing chamber of thebag at a lower fabrication and material cost without the need ofaltering the bag thickness. The air channel is formed on a first airimpermeable layer or a second air impermeable layer through injection bydirectly forming a folding line on the first air impermeable layer orthe second air impermeable layer. When the plastic bag is coupled with asealing machine, the remained air inside the housing chamber can befully extracted through the air channel before sealing process isstarted.

The foregoing, as well as additional objects, features and advantages ofthe invention will be more readily apparent from the following detaileddescription, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of the presentinvention.

FIG. 2 is a schematic view of the first embodiment of the presentinvention in a fabrication condition.

FIG. 3 is a perspective view of a second embodiment of the presentinvention.

FIG. 4 is a schematic view of the second embodiment of the presentinvention in a fabrication condition.

FIG. 5 is a front view of the bag opening of the first embodiment of thepresent invention.

FIG. 6 is a front view of the bag opening of a third embodiment of thepresent invention.

FIG. 7 is a front view of the bag opening of a fourth embodiment of thepresent invention.

FIG. 8 is a front view of the bag opening of a fifth embodiment of thepresent invention.

FIG. 9 is a schematic view of the invention coupling with a sealingmachine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please referring to FIGS. 1, 2 and 5, the plastic bag 10 according tothe invention has a bag opening 14 and may be sealed by a sealingmachine 20. The plastic bag 10 consists of a first air impermeable layer11 and a second air impermeable layer 12 made from an air impermeablematerial that are bonded together by thermal pressing or supersonicfusion to form a housing chamber 13. Referring to FIG. 2, the plasticbag 10 has a selected length with the bag opening 14 on one endcommunicating with the housing chamber 13, and a closed end 16 on otherend connecting to the bag opening 14 of another plastic bag 10.Referring to FIGS. 3 and 4, the plastic bag 10 may also have only thebag opening 14 on one end. Users can cut off the bag at a length desiredaccording to the quantity of goods to be contained inside.

The main feature of the invention is to form at least one air channel 15a on the first impermeable layer 11 or the second air impermeable layer12. The air channel 15 a is formed by fabricating at least one foldingline a on the first impermeable layer 11 or the second air impermeablelayer 12 during the integrated injection molding process of the plasticbag 10. The folding line a may be one line or double lines b and c.Refer to FIG. 5 for the air channel 15 a formed by a single folding linea that is located outside the housing chamber 13. FIG. 6 illustrates thedouble lines b and c that form two air channels 15 b and 15 c outsidethe housing chamber 13 that have a jointed passage 151 at the front endcommunicating with the housing chamber 13. FIG. 7 shows another form ofdouble folding lines b and c that form two air channels 15 b and 15 coutside the housing chamber 13 that communicate with the housing chamber13 separately. Referring to FIG. 8, the folding line a may also beformed respectively on the first impermeable layer 11 and the second airimpermeable layer 12 to form respectively an air channel 15 a thereon.

Refer to FIG. 9 for the invention coupling on a sealing machine 20. Theplastic bag 10 is coupled on a suction mechanism 21 of the sealingmachine 20 (the sealing machine 20 may have various structures. In thisembodiment shown in the drawings only the suction mechanism 21 and aheat sealing mechanism 22 are indicated for discussion purpose). Whenthe heat sealing mechanism 22 clamps the plastic bag 10 on the upperside and the lower side, the sealing machine 20 may be activated, andthe suction mechanism 21 starts extracts air from the plastic bag 10. Asthe plastic bag 10 has the air channel 15 a leading to the housingchamber 13 from the bag opening 14, the design of the folding line a canprevent the mistaken judgement of air suction were completed caused bythe closing of the bag opening 14 at the initial air suction stage bythe suction mechanism 21 so that the remaining air in the housingchamber 13 may be fully extracted. After the suction mechanism 21 hasfinished air extraction, the heat sealing mechanism 22 is activated toseal the bag opening 14 of the plastic bag 10. As the invention does notneed to increase the thickness of the plastic bag 10, sealing of theplastic bag 20 can be accomplished rapidly, and the possibility of theexternal air to reenter the housing chamber 13 through the air channel15 a decreases.

By means of the construction set forth above, the plastic bag 10 of theinvention may be made without adding material. The cost is lower andfabrication process also is simpler. Thus total production cost may bereduced. In addition, the sealing time does not increase, and air returnflow may also be reduced.

While the preferred embodiments of the invention have been set forth forthe purpose of disclosure, modifications of the disclosed embodiments ofthe invention as well as other embodiments thereof may occur to thoseskilled in the art. Accordingly, the appended claims are intended tocover all embodiments which do not depart from the spirit and scope ofthe invention.

1. A plastic bag to be coupled with a vacuum sealing machine,comprising: a first air impermeable layer and a second air impermeablelayer bonded to form a housing chamber to hold goods having at least onebag opening communicating with the housing chamber; and at least one airchannel selectively formed on the first air impermeable layer or thesecond air impermeable layer by forming at least one folding line on thefirst air impermeable layer or the second air impermeable layer thatcommunicates the bag opening with the housing chamber; wherein theplastic bag is coupled with the vacuum sealing machine so that remainingair in the housing chamber is extracted by the sealing machine throughthe air channel, and the bag opening is sealed thereafter.
 2. Theplastic bag of claim 1, wherein the folding line is a single foldingline to form the air channel outside the housing chamber.
 3. The plasticbag of claim 1, wherein the folding line is double folding lines to formtwo air channels outside the housing chamber that have a joint passageon the front end of the housing chamber.
 4. The plastic bag of claim 1,wherein the folding line is double folding lines to form two airchannels outside the housing chamber to communicate respectively withthe housing chamber.
 5. The plastic bag of claim 1, wherein the foldingline is formed respectively on the first air impermeable layer and thesecond air impermeable layer to form respectively an air channel on thefirst air impermeable layer and the second air impermeable layer.